Recombinant Human Aminopeptidase B/RNPEP Protein, CF

• Reactivity: Hu
• Applications: Enzyme Activity
• Format: Carrier-Free

Recombinant Human Aminopeptidase B/RNPEP Protein, CF Summary

• Details of Functionality: Measured by its ability to cleave the fluorogenic peptide substrate, Arg-7-amido-4-methylcoumarin (Arg-AMC). The specific activity is >8,000 pmol/min/μg, as measured under the described conditions.
• Source: Spodoptera frugiperda, Sf 21 (baculovirus)-derived human Aminopeptidase B/RNPEP protein
  Met1-Ser650, with a C-terminal 10-His tag
• Accession #: Q9H4A4
• N-terminal Sequence: Inconclusive: Met1 predicted. Protein identity confirmed by MS analysis of tryptic fragments.
• Protein/Peptide Type: Recombinant Enzymes
• Gene: RNPEP
• Purity: >95%, by SDS-PAGE under reducing conditions and visualized by Colloidal Coomassie® Blue stain at 5 μg per lane.
• Endotoxin Note: <0.01 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Enzyme Activity
• Theoretical MW: 74 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 60-70 kDa, reducing conditions

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 6 months from date of receipt, -20 to -70 °C as supplied.
  • 3 months, -20 to -70 °C under sterile conditions after opening.
• Buffer: Supplied as a 0.2 μm filtered solution in Tris, NaCl and Glycerol.
• Purity: >95%, by SDS-PAGE under reducing conditions and visualized by Colloidal Coomassie® Blue stain at 5 μg per lane.
• Assay Procedure:
  • Assay Buffer: 50 mM Tris, 100 mM KCl, 1 mM DTT, pH 7.5
  • Recombinant Human Aminopeptidase B/RNPEP (rhRNPEP) (Catalog # 8089-ZN)
  • Substrate: H-Arg-AMC (Chem-Impex, Catalog # 05859), 10 mM stock in DMSO
  • F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
  • Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent
  1. Dilute rhRNPEP to 0.2 ng/µL in Assay Buffer.
  2. Dilute Substrate to 400 µM in Assay Buffer.
  3. Load 50 µL of 0.2 ng/µL rhRNPEP to a plate in triplicate, and start the reaction by adding 50 µL of 400 µM Substrate. Include a Substrate Blank containing 50 µL of Assay Buffer and 50 µL of Substrate.
  4. Read at excitation and emission wavelengths of 380 nm and 460 nm, respectively in kinetic mode for 5 minutes.
  5. Calculate specific activity:

  Specific Activity (pmol/min/µg) = (Adjusted Vmax* (RFU/min) x Conversion Factor** (pmol/RFU)) / (amount of enzyme (µg))

  *Adjusted for Substrate Blank
  **Derived using calibration standard 7-amino, 4-Methyl Coumarin (Sigma, Catalog # A-9891).

  Per Well:
  • rhRNPEP: 0.01 µg
  • Substrate: 200 µM

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant Human Aminopeptidase B/RNPEP Protein, CF

• Aminopeptidase B
• APB
• AP-B
• Arginine aminopeptidase
• arginyl aminopeptidase (aminopeptidase B)
• Arginyl Aminopeptidase
• DKFZp547H084
• EC 3.4.11
• EC 3.4.11.6
• RNPEP

Background

Aminopeptidase B (APB; also known as aminopeptidase basic, Arginine aminopeptidase and RNPEP) is a monomeric, secreted member of the metallopeptidase M1 family of enzymes (1-2).  Members of the M1 family are often associated with mitosis, and are characterized by the presence of a catalytic domain that consists of a GxMxN exopeptidase motif, coupled to an extended Zn-binding HExxH[18x]E sequence (1, 3).  Although Zn-dependent, it is activated by divalent cations such as Ni, Mn and Co.  APB is widely expressed, perhaps even ubiquitously, and has been reported in a number of distinct cell types.  These include hepatocytes (4), skeletal muscle cells (5), macrophages and neutrophils (6), pancreatic islet  alpha -cells (7), anterior lobe pituitary basophils (8), and adrenal medullary chromaffin cells (8).  APB has been identified in multiple subcellular locations, including an extracellular association with the plasma membrane, within secretory granules of neuroendocrine cells, and through an NLS, within the cell nucleus (1, 7-11). APB appears to act in concert with at least one other peptidase during the processing of propeptides into active or mature peptides.  The activity attributed to APB involves the preferential cleavage of the basic amino acids (aa) Arg and Lys from the N-terminus of partially processed proforms (9).  This activity is reported to occur in alpha -cell granules where an NRD convertase:APB cooperation converts glucagon into miniglucagon (aa 19-29), and in adrenal medullary chromaffin cell granules where a cathepsin L:APB cooperation converts proenkephalin into Met-enkephalin (7, 8).  The human APB precursor is 650 aa in length.  It contains an atypical 28 aa signal sequence plus a 622 aa mature region that contains a peptidase region over aa 24-634 (10, 12).  A leukotriene A4 hydrolase has also been described between aa 500-644.  Mature APB is reported to run as a 72-76 kDa protein on SDS-PAGE (5, 8, 10, 11).  There are potential isoform variants.  One shows a 12 aa substitution for aa 11-14, while another may utilize an alternate start site at Met291.  Mouse and rat APB share 89% aa sequence identity with human APB.

1. Luan, Y. et al. (2012) Curr. Protein Pept. Sci. 13:490.
2. Foulon, T. et al. (1999) Int. J. Biochem. Cell Biol. 31:747.
3. Peer, W.A. (2011) Ann. Botany 107:1171.
4. Kato, S. et al. (1979) J. Biochem. 86:1419.
5. Ishiura, S. et al. (1987) J. Biochem. 102:1023.
6. Aoyagi, T. et al. (1978) Cancer Res. 38:3505.
7. Fontes, G. et al. (2005) Endocrinology 146:702.
8. Hwang, S-R. et al. (2007) J. Neurochem. 100:1340.
9. Pham, V-L. et al. (2007) BMC Biochem. 8:21.
10. Belhacene, N. et al. (1993) Eur. J. Immunol. 23:1948.
11. Balogh, A. et al. (1998) J. Cell Sci. 111:161.
12. Piesse, C. et al. (2002) Gene 292:129.

Bioinformatics

• Gene Symbol: RNPEP
• Uniprot:
  • Q9H4A4()